Thermostatic water-mixer



M. 0. SNEDIKER.

THERMOSTATIC WATER MIXER.

APPLICATION FILED DEC. 28.1917.

1,397,707. Patented Nov. 22, 1921.

C LD WHTEK HOT WfiTE K UNITED STATES PATENT OFFICE.

l MORTON O. SNEDIKER, OF CHICAGO, ILLINOIS, ASSIGNOB TO THE POWERS REGU- LA'IOR COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

'rn'namosrarrc WATER-MIXER.

Specification of Letters Patent.

Patented Nov. 22, 1921.

Application filed December 28, 1917. Serial No. 209,365.

To all whom it may concern Be it known that I, MORTON O. SNEDIKER, a citizen of the United States, and resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in a Thermostatic Water-Mixer, of which the following is a specification.

My invention relates to means for controlling the temperature of mixed liquids of different temperatures, and particularly to an improvement on the construction sliown in the. prior patents to Powers and Snediker, N 0. 1,195,722, dated August 22, 1916, and to Snediker, N 0. 1,243,999, dated Oct. 23, 1917.

An object in the construction of the pres ent device is to provide ina single instrument means for securing a much wider range of adjustment whereby relatively higher.- and lower temperatures of the mixed fluids may be secured. In the use of thermostats of the type shown in the prior patents referred to, a liquid is employed having a low atmospheric boiling point, the pressure developed by the vaporization of the fluid at a temperature above the boiling point serving as the actuating means for the thermostat. It has been found that the range of temperature controlled by such use of liq uids is relatively small, being limited at the low extreme by the boiling point of liquid under atmospheric pressure and at the high point by the strength of the regulating device and its ability to withstand the high pressure developed. The regulating device, which is usually in the form of a collapsible bellows, must be constructed of suificiently thin gage material to be responsive to slight pressure changes and when thus constructed will not withstand high pressures. In practice if a liquid is employed having an atmospheric boiling point sufficiently low to secure temperature adjustments as low as 70 F it will, of course, be installed at a temperature below its boiling point.

n the present device I eliminate the internal air pressure and employ the external pressure as a means for resisting the excessive pressure developed at high temperatures. A relatively high-boiling point liquid is placed in the container and all the air exhausted therefrom. This, of course, reduces the boiling point of the liquid to what may be termed its in vacuo boiling po nt, which point is below the lowest regulat ng temperature desired. At the in cacao bolling point of the liquid, there is what may be termed a minus pressure of 14.7 lbs. per sq. in., representing the air pressure which must be overcome before there is any pressure developed which has a tendency to disrupt the container. Regulation of temperaturesup to this point may there-- fore be effected with no strain whatever on the container. When the point is reached at whlch the vapor tension balances the air pressure, the conditions for the control of higher temperatures will be identical with those in which the same liquid was installed at atmospheric pressure. However, in order to secure temperature control at points below and above the point of balanceo'f vapor tension and air pressure, means must be provided for wholly or partially neutralizmg the air pressure in the first instance, and augmenting the air pressure in the second instance. This may be accomplished by the use of an adjustable weight or spring so arranged as to alternately exert its force against or with the air pressure.

For instance, if the air were exhausted from the thermostatic container no regulation would be had except at such temperature that the vapor tension balanced the air pressure, which temperature would be equal to the boiling point of the thermostatic liquid at atmospheric pressure. If adjustment is to be had at lower temperatures, the air pressure must be offset to the required degree. In that manner regulation may be effected for all temperatures above the in cacao boiling point of the thermostatic liquid.

If temperatures are to be controlled above the point of balance of the vapor tension and air pressure, the air pressure must be augmented; in other words, above the point of balance the regulation is effected in the usual manner.

The fundamental point is that a pressure of 14.7 lbs. per sq. in., (at sea level) is subtracted from the pressure within the thermostatic coniainer and control is effected between the in vacuo boiling point of the liquid and the desired high limit without the creation of an effective distorting force, the results being secured by subtracting from and adding to the pressure exerted by the atmosphere.

Theinvention will be more readily understood by reference to the accompanying drawings, wherein,

Figure 1 is a vertical, sectional view thrmgh a controller constructed in accordance with my invention, and,

Fig. 2 is a section on the line 2-2 of Fig. 1.

In the drawings it will be seen that the device includes a casing 10, having two inlets 11, 12, for hot and cold fluids respectively, and an outlet 13, for the tempered fluid, which is located in a shell 14, or supplementary casing, secured to the casing 10. A1 two-faced valve 15, is secured to a long stem 16, the two faces of the valve alternately cooperating with seats 17, 18, in the casing 10, serving to control the admission of the hot and cold fluids respectively. The lower end of the stem 16, is threaded within a flanged nut 19, which is securely clamped by means of the nut 20, to the lower diaphragm 21, of a series which constitute a bellows. The upper diaphragm 22, of the series is rigidly secured by means of a threaded plug 23, to the casing 10. Thus the expansion and contraction of the bellows controls the movement of the valve 15.

The valve-actuating bellows is placed within a rigid shell located within the supplementary casing 14, the shell consisting of bottom and top walls 24, 25, and a noncollapsible, cylindrical side wall 26. The space 34, between the rigid shell and the collapsible bellows is adapted to contain the thermostatic fluid. It will be noted that the interior of the bellows defined by the diaphragms 21, 22, is in communication with the atmosphere through the vent opening 35, and the space allowed around the stem 16. A small quantity of a thermostatic liquid having the desired boiling point, such as alcohol, is placed within the space 34, constituting the thermostatic control space, a vent opening being left in the rigid container. 'Heat is then applied to the rigid container to vaporize a quantity of the liquid and thereby to eject all air from the space 34. When this has been accomplished, the vent opening is sealed and upon resumption of normal temperature conditions there will be a vacuum within the space 34. Thus the atmospheric boiling point of the thermostatic liquid will be lowered and its in cacao boiling point will be considered from this point. A liquid will be selected whose in 'vacuo boiling point is below the low limit of control intended to be effected and therefore it will be seen that the thermostatic element is in the form of vapor at all regulating temperatures. This is an important point. In any device in which the control must be effected by expansion of a liquid or by a change from the liquid to gaseous state, considerable time must be allowed for At the in 'vacuo boiling point of the thermostatic liquid there is in the space 34, what mlght be termed a minus pressure of 14.7 lbs. per sq. in. (at sea level); that is, air pressure entering through the vent 35, is exerted on the bellows tending to expand the same and therefore tending to pull the valve 15, toward the seat 18, and to open the hot fluid inlet. If no means for controlling this force were employed, hot water would be admitted until the temperature around the casing 26, became such that the vapor within the space 34, was expanded until it had a tenslon equal to 14.7 lbs. per sq. in., at which point the valve 15, would be maintained in such position as to retain this temperature. This temperature of the fluid would be found to equal the atmospheric boiling point of the liquid employed. If it is now desired to regulate temperatures at the lower points the atmospheric pressure must be neutralized or offset to the desired degree. If the atmospheric pressure was entirely neutralized, control might be effected down to substantially the 'z'm. 'vacuo boiling point of the liquid employed.

If, on the other hand, control is desired above the atmospheric boiling point of the liquid, the atmospheric pressure must be augmented. In order to accomplish these results I employ mechanism consisting of a beam 29, fulcrumed at 30, on a link which is pivoted at 31, to a casing bracket 32, secured to the casing 10. Thebeam is likewise connected at 33, to the upper end of the valve stem 16. It will be noted that the beam has two arms 27, 28, located on opposite sides of the fulcrum, the weight 27, being adapted to slide along and be secured in difierent positions on either of the two arms. It is held in adjusted position by the thumb-screw 27". A spring 36, of small capacity, is connected tothe beam and to a support and serves the purpose of stabilizing the beam and preventing pulsations during a change in the adjustment. By this means the beam will quickly come to a balance following a change.

For the purpose of illustration it will be assumed that a liquid is employed having an atmospheric boiling point of substantially 120 F., such as carbon bisulfid and'an in 'vacuo boiling point of approximately 60 F. If it be desired to accurately control temperatures below the atmospheric boiling point, the weight 27, is mounted on the end 27 of'the beam and located at the proper point whereby to secure the desired temperature. This location of the weight serves to exert an upward pull on the stem 16, and to partially or Wholly neutralize the atmospheric pressure exerted on the inside of the bellows.

If, however, it is desired to control the temperatures at points above the atmospheric boilin point of the fluidapproximately 120 in this casethe weight is mounted on the opposite end 28, of the beam. This serves to reverse the conditions just described and to augment the atmospheric pressure within the chamber 34'. By the use of the means described, temperature control between approximately 70 F. and 180 F. is possible without excessive pressure. Other ranges may be secured with other liquids having different boiling points.

It will be understood that the term in ammo is used in its relative sense and when employed in the claims is considered to relate to conditions in which an incomplete or Ipartial vacuum is employed.

am aware that the desired result may be secured in a different manner, as for instance by employing springs as the equivalent of the weight illustrated. Weights are preferable, however, because of their unvarying accuracy and non-accumulative resistance to movement.

I claim:

1. In a controller, the combination of a casing havinginlets for hot and cold fluids, and an outlet for the tempered fluid, a valve for regulating the quantity of each fluid admitted, a stem for said valve, a fluid-pressure thermostat including a diaphragm, said stem being connected to the diaphragm, and mechanical means for selectively exerting pressure against said diaphragm in opposite directions, substantially as described.

2. In a thermostatic regulator, the combination of a casing having inlets for hot and cold fluids, and an outlet for the tempered fluid, a reciprocating valve for controlling admission of the hot and cold fluids, a valve stem, a rigid, non-collapsible container mounted in the path of the liquids toward the outlet, 2. collapsible element mounted for regulating the quantity of each fluid admitted, a stem for said valve, a fluid-pressure thermostat connected to said stem, a beam, and a weight adapted for movement on said beam to selectively subtract from and add to the atmospheric pressure exerted on said thermostatic element, substantially as described.

4. In a regulator, the combination of a conduit for fluids, of a valve for controlling said fluids, a stem for said valve, a fluidpressure thermostat connected to said stem, a beam operatively connected to said thermostat and said stem, and a weight adapted.

for movement on said beam to selectively subtract from and add to the atmospheric pressure exerted on said thermostat, substantially as described.

5. In a controller, the combination of a casing, a valve mounted in said casing for controlling the passage of fluid therethrough, a valve stem, a thermostat in the form of a collapsible bellows adapted to contain a heat-sensitive liquid, a beam opera tively connected to said thermostat and stem, and a weight movable along said beam and adapted to be positioned on opposite sides of the fulcrum thereof whereby the force exerted by the weight may be applied to selectively subtract from and add to the atmospheric pressure exerted on said bel-' MORTON O. SNEDIKER.

Witness T. D. Burma. 

